黄渤海表层水及滨海盐渍化土壤中蓝细菌多样性及分布
其他题名环境生物学
李寒
学位类型硕士
导师龚骏
2015
学位授予单位中国科学院研究生院
学位授予地点北京
学位专业环境科学
关键词蓝细菌 聚球藻 原绿球藻 盐度梯度土壤 表层水 时空变化 群落结构 多样性 丰度
摘要1.蓝细菌具有独特的光能固碳与固氮机制,其存在对于改良退化土壤具有重要意义。目前关于土壤盐渍化对蓝细菌多样性及分布的影响研究较少。本研究以莱州湾区域滨海盐渍化土壤中的蓝细菌为研究对象,调查蓝细菌在不同盐度下的群落组成及分布情况。利用自动核糖体间隔基因分析(ARISA)技术、群落相似性分析(ANOSIM)技术、克隆文库、测序、荧光定量PCR以及系统发育分析等方法,探究盐渍化土壤中蓝细菌群落结构及丰度分布。通过BEST多元分析研究主要环境因子对蓝细菌群落的影响。结果显示:蓝细菌在莱州湾南岸及黄河口附近土壤中区域广泛存在,且其群落结构在盐度梯度间差异显著(P=0.03)。在所有检测的环境因子中,土壤盐度以及土壤水分含量对蓝细菌群落结构的影响最为显著(P=0.02)。不同盐度土壤环境中,蓝细菌优势类群组成差异较大,其中低盐梯度样品中,蓝细菌的群落多样性及丰富度最低,HalomicronemaAcaryochloris为优势类群。中、高盐梯度中,Leptolyngbya为优势类群。特殊类群ArthrospiraGeitlerinema只在低盐土中检测到,高盐土壤中特有的种是Oscillatoria。蓝细菌丰度随着盐度的变化而变化,整体上呈现盐度越高,丰度越低的态势。其中低盐样品丰度最高,为2.14×105 copies·g-1干土,中盐(1.25×105 copies·g-1干土)与低盐之间存在显著差异(P<0.05),低盐高于中盐;高盐度土为1.20×105 copies·g-1干土,中高盐度之间差异不显著。总之,土壤盐渍化程度以及土壤水含量是调控莱州湾南岸滨海土壤中蓝细菌群落结构与丰度的重要因子,可能对滨海土壤微生物碳氮循环产生影响。
2.蓝细菌在全球海洋碳氮循环中发挥着重要作用,尤其是在寡营养盐海域,蓝细菌更是初级生产力的主要贡献者。本工作主要利用流式细胞术分析了黄渤海表层水中蓝细菌(聚球藻和原绿球藻)及其他主要浮游生物类群(粒径<20μm)(包括皮微级及纳微级浮游植物、隐藻、异养浮游细菌中的高核酸含量HNA及低核酸含量LNA类群)的丰度分布,并分析蓝细菌丰度随时空的变化以及与主要浮游生物类群和水质因子的相关关系。结果发现,总蓝细菌丰度在春秋两季各海区均无显著差异(P>0.05);蓝细菌类群以聚球藻为主,其丰度要明显高于原绿球藻;在黄海中南部海域,各类群丰度均较高,渤海及北黄海相对较低。聚球藻丰度秋季较高(均值为2.6×104 cell·ml-1,最高可达2.90×105 cell·ml-1),而春季相对较低(均值为2.4×104 cell·ml-1),但是季节差异不显著(P>0.05)。
本研究首次在黄渤海表层水中检测到原绿球藻的广泛存在(丰度最高可达7.5×104 cell·ml-1),原绿球藻丰度春季(均值为5.5×103 cell·ml-1)大于秋季(均值为672 cell·ml-1),且在渤海以及黄海北部海域季节差异极显著(P<0.01)。通过对春秋两季各类群丰度的相关分析显示,随时空的变化各类群之间的相关性也发生相应的变化。其中,各类群之间在秋季呈现较为紧密的相关关系,而春季则相关性不明显;聚球藻与原绿球藻二者在多数海区均具有较为显著的正相关关系,这可能还与水体中环境因素的影响有关。通过BEST分析发现,在秋季,温度、溶解氧以及硝酸盐含量的组合对所检测浮游生物整体丰度的影响较为显著(R=0.398;P=0.002);在春季,温度、溶解氧、盐度以及叶绿素a含量的组合对浮游生物丰度影响最为显著(R=0.444;P=0.002)。聚球藻蓝细菌丰度主要受温度、硝酸盐含量等因素的影响,且在不同海区、不同季节有较大差异;原绿球藻主要与pH以及叶绿素a含量相关,且在不同时空条件下的响应机制各不相同。本文调查分析了蓝细菌在黄渤海表层水体中的时空分布特点以及与环境因子的关系,为理解蓝细菌在黄渤海表层水中的生态作用与贡献提供了数据参考。
其他摘要1. Little is known about the diversity and distribution of cyanobacteria in salinized soils. In this study, we determined soil properties (pH, salinity and water contents, ammonium, nitrite, nitrate, total organic carbon and nitrogen), and investigated the molecular diversity and distribution patterns of soil cyanobacteria at 12 sites near the mouth of Yellow River and in the southern coastal plain of Laizhou Bay (Shandong province), typical salinized coastal regions in China. Salinity gradients were devided into three ranges: low (0.63%~1.27%), medium (1.55%~2.00%), and high saline (2.39%~5.11%). Automated ribosomal intergenic spacer analysis (ARISA), clone libraries and real-time quantitative PCR were used to determine the cyanobacterial community structure, composition and abundance, respectively. Based on ARISA fingerprints, we found cyanobacterial phylotype richness increased with salinity; multiple dimensional scaling and hypothesis testing (ANOSIM) indicated that the community structure of cyanobacteria generally clustered by salinity (P=0.03) more than by water content (P=0.09). Biota-Environment correlation (BEST) analysis further revealed that a combination of two factors, salinity and water content of soils, could mostly explain the changes in cyanobacterial community structure (P=0.02). Clone libraries of 16S rRNA gene were constructed for 3 representative samples. Sequencing and classification following phylogenetic analysis showed that Halomicronema and Acaryochloris dominated in the low saline samples, whereas Leptolyngbya was the most abundant in both medium and high saline soils. Another two taxa, Arthrospira and Geitlerinema, were only found in the samples of low salinity, while Oscillatoria was detected once from the high salinity. Cyanbacterial 16S rRNA genes were much more abundant in low salinity (2.14×105copies·g-1 dry soil) than in medium (1.25×105copies·g-1 dry soil) and high salinity samples (1.20×105copies·g-1 dry soil). This study demonstrates that salinity shapes the diversity, community structure and abundance of cyanobacteria in the saline soils, which has implications for carbon and nitrogen cycling contributed by these microorganisms in coastal terrestrial ecosystems.
2. Cyanobacteria play an important role in global marine carbon and nitrogen cycles.Using flow cytometry, we investigated the abundance of cyanobacteria (Synechococcus and Prochlorococcus), and other planktons including picopyhtoplankton, nanophytoplankton, Cryptophyta, and heterotrophic bacterioplanktons of high nucleic acid contents (HNA) and of low nucleic acid contents (LNA), in surface waters of the Bohai Sea and Yellow Sea in the autumn of 2013 and in the spring of 2014. Temporal and spatial variations of cyanobacterial abundances were assessed and the relationships with other planktons and with major physicochemical factors were evaluated using correlation analysis. Results showed that cyanobacterial abundances had no difference for the temporal and spatial variations (P>0.05). Synechococcus was apparently more abundant than Prochlorococcus. High abundances of plankons were found in the southern and the central Yellow Sea; whereas relative low abundances were observed in Bohai Sea and the northern Yellow Sea. Abundant Synechococcus cells were found in the autumn of 2013 (mean 2.6×104 cell·ml-1, maximum 2.90×105 cell·ml-1) and in the spring of 2014 (mean 2.4×104 cell·ml-1). Seasonal variation of Synechococcus was insignificant (P>0.05).
The abundance of Prochlorococcus was much higher in spring (5.5×103 cell·ml-1) than in autumn (672 cell·ml-1). Seasonal difference of Prochlorococcus abundance was found in the Bohai and north Yellow Seas (P<0.01). Pearson correlations of abundances of major planktons showed distinctions in different regions and seasons. Higher correlation coefficients were found in autumn than in spring. In most of the regions, Synechococcus and Prochlorococcus showed significantly positive correlations with each other, indicating environmental factors may play an important role in shaping the distribution of cyanobacteria. Biota-Environment correlation (BEST) analysis indicated that the combination of temperature, dissolved oxygen and the concentration of nitrate could mostly explain the distribution patterns of the planktons in autumn (R=0.398;P=0.002). In spring, however, the most important factors were temperature, dissolved oxygen, salinity and the concentration of chlorophyll a(R=0.444;P=0.002). Temperature and nitrate concentration had significant effects on the abundance of Synechococcus, whereas the abundance of Prochlorococcus was mostly correlated with pH and chlorophyll a concentration. The wide distribution of Prochlorococcus in the P-limited Bohai Bohai and Yellow Seas, reflects the adaptation of Prochlorococcus in low-phosphate water. 
语种中文
文献类型学位论文
条目标识符http://ir.yic.ac.cn/handle/133337/7931
专题中国科学院烟台海岸带研究所知识产出_学位论文
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李寒. 黄渤海表层水及滨海盐渍化土壤中蓝细菌多样性及分布[D]. 北京. 中国科学院研究生院,2015.
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